In recent years, various input methods have been employed for computers, game machines and the like. For example, a system has been proposed which recognizes a motion of an operator such as a predefined gesture through the imaging thereof using a camera or the like and determines to which of operational contents the gesture corresponds. For example, PTL1 proposes a technology of enabling a very easy and convenient apparatus operation without necessity of an input apparatus such as a mouse, and the technology includes: a host computer recognizing the shape and the motion of an object in an image imaged by a CCD camera; and a display displaying the shape and the motion of the object recognized by the host computer, and wherein, when a user gives an instruction by means of a hand gesture or the like while being faced to the CCD camera, the given hand gesture is displayed on a display screen of the display and a virtual switch or the like displayed on the display screen can be selected using an icon of an arrow cursor by means of a hand gesture.
On the other hand, in operating a computer, an operator matches a pointer with a predetermined position such as a button or an input field displayed on a display by moving a mouse, and settles an operational content such as “pressing the button” or “starting inputting into the input field” by making a click or the like. Thus, conventionally using a mouse, pointing or focusing (selecting) is executed and a click button is pressed once in a predetermined position, whereby selection of the position or the like can be executed. Furthermore, various applications associated with pointed positions can be executed by consecutively pressing the click button twice (so called double-click). Alternatively, such operation as drag for connecting a pointed position to a destination is enabled. An input keyboard is normally used for inputting a piece of specific information such as a numeric value or a character, and therefore, an operator outputs a piece of desired information or inputs a piece of necessary information and is supposed to repeat moving by means of the mouse and inputting by means of the keyboard.
Furthermore, to achieve enhancement in convenience regarding an operation of an operator without requiring an operator to wear a special apparatus, a technology has been proposed that enables an operator to perform a click operation, a drag operation, a double-click operation and the like as a mouse operation with respect to a display image and to draw and input a desired line, diagram, character or the like by defining a virtual plane G or a virtual keyboard H, for instance, in an appropriate space part as operating means corresponding to a keyboard, a mouse or the like (e.g., see PTL2).